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International audience; The new SPIRAL2 LINAC at GANIL delivers light beams (p, d, alpha,…) with very large intensities. In order to exploit these beams in an optimal way, high power target stations are requested. In this contribution, we present such an irradiation station designed to optimize the production of 211 At, an alpha emitter of interest for targeted alpha therapy. In order to dissipate at least 10 kW of beam power, a rotating, water-cooled system comprising twelve individual targets has been developed together with a fast and safe extraction mechanism.

The SPIRAL2 injector includes a 5 mA proton-deuteron ECR source, a 1 mA ECR heavy ion source (up to A/Q =3) and a CW 0.73 MeV/u RFQ. It has been successfully commissioned using a diagnostic-plate in parallel with the superconducting linac installation. The green light has been obtained for the LINAC commissioning in July of 2019, starting with the Medium Energy Beam Transport (MEBT) commissioning with protons then with helium in 2020. The MEBT line and tuning process are described. The main experimental results are given, including the emittance and profile measurements which are compared with TraceWin simulations. RFQ output energy variation has been found due to an input energy error, its correction optimizing the source platform voltage is presented., Proceedings of the 12th International Particle Accelerator Conference, IPAC2021, Campinas, SP, Brazil

A novel experimental analysis method has been developed, making use of the continuous wavelet transform and machine learning to rapidly identify α-clustering in nuclei in regions of high nuclear state density. This technique was applied to resonant scattering measurements of the 4He(40,44,48Ca,α) resonant reactions, allowing the α-cluster structure of 44,48,52Ti to be investigated. Fragmented α-clustering was identified in 44Ti and 52Ti, while the results for 48Ti were less conclusive, but suggest no such clustering.

The SPIRAL1 charge breeder (SP1CB) is under opera-tion. Radioactive ion beam (RIB) has already been deliv-ered [1] to Physicist for experiments. Charge breeding efficiencies demonstrated high performances for stable ion beams than RIB’s. The beam optics, prior to the injection of the 1+ ions into the SP1CB, is of prime im-portance [2] for obtaining such high efficiencies. Moreo-ver, the intensities of the RIB’s are so low, and indeed difficult to tune the SP1CB. A stable beam having a close B’ is required to find out the set of optic parameters preceding the tuning of the RIB. Hence, it has been de-cided to focus our effort on the control of 1+ beam optics leading to high charge breeding efficiencies whatever the 1+ mass, energy and Target Ion Source System (TISS) used. This contribution will show the strategy undertaken to overcome that problem and the results obtained., Proceedings of the 24th International Workshop on ECR Ion Sources, ECRIS2020, East Lansing, MI, USA

International audience; A novel technique has been developed, making use of the continuous wavelet transform to identify α-clustered states from resonant scattering measurements in regions of high nuclear state density. This technique expedites the investigation of α clustering in medium mass and heavy nuclei where the role that α clustering plays in the structure of the nucleus is poorly understood. Here, we report the application of this technique to measurements of the He4(Ca40,44,48,α) resonant reactions, leading to an assessment of the α-cluster structure of Ti44,48,52. Clustering involving α particles was identified in Ti44 and Ti52 but was observed to break down in Ti48. The implications of these results are discussed.

A novel technique has been developed, making use of the continuous wavelet transform to identify a-clustered states from resonant scattering measurements in regions of high nuclear state density. This technique expedites the investigation of alpha clustering in medium mass and heavy nuclei where the role that alpha clustering plays in the structure of the nucleus is poorly understood. Here, we report the application of this technique to measurements of the He-4(Ca-40, 44, 48, alpha) resonant reactions, leading to an assessment of the alpha-cluster structure of Ti-44, 48, 52. Clustering involving alpha particles was identified in Ti-44 and Ti-52 but was observed to break down in Ti-48. The implications of these results are discussed.

The lifetimes of the first excited 2þ, 4þ, and 6þ states in 98Zr were measured with the recoil-distance Doppler shift method in an experiment performed at GANIL. Excited states in 98Zr were populated using the fission reaction between a 6.2 MeV=u 238U beam and a 9 Be target. The γ rays were detected with the EXOGAM array in correlation with the fission fragments identified by mass and atomic number in the VAMOS++ spectrometer. Our result shows a very small BðE2; 2þ 1 → 0þ 1 Þ value in 98Zr, thereby confirming the very sudden onset of collectivity at N ¼ 60. The experimental results are compared to large-scale Monte Carlo shell model and beyond-mean-field calculations. The present results indicate the coexistence of two additional deformed shapes in this nucleus along with the spherical ground state.

The lifetimes of the first excited 2+, 4+, and 6+ states in Zr98 were measured with the recoil-distance Doppler shift method in an experiment performed at GANIL. Excited states in Zr98 were populated using the fission reaction between a 6.2 MeV/u U238 beam and a Be9 target. The γ rays were detected with the EXOGAM array in correlation with the fission fragments identified by mass and atomic number in the VAMOS++ spectrometer. Our result shows a very small B(E2;21+→01+) value in Zr98, thereby confirming the very sudden onset of collectivity at N=60. The experimental results are compared to large-scale Monte Carlo shell model and beyond-mean-field calculations. The present results indicate the coexistence of two additional deformed shapes in this nucleus along with the spherical ground state. © 2018 American Physical Society.

This work is a theoretical study of the spinodal decomposition of nuclei which is directly connected to liquid-gas phase transitions of the nuclear matter. This mechanism could be responsible for the multifragmentation observed in nucleus-nucleus collisions at the Fermi range energy. First, we show on a classical exemple that mean field approximation are suitable to investigate the dynamics of many-particle system inside the spinodal region. Then we determine which modes could produce the fragmentation of the nucleus with mean field approaches. We discuss the role of non-linearities, temperature, finite size effects, the range of the force and quantum effects on the development of instabilities., Cette thèse est une étude théorique de la décomposition spinodale dans les noyaux qui est directement reliée aux transitions de phase liquide-gaz de la matière nucléaire. Ce type de mécanisme pourrait être responsable de la multifragmentation observée dans les collisions noyau-noyau aux énergies de Fermi. Nous montrons tout d'abord dans un exemple classique que les approximations de champ moyen sont tout à fait adaptées pour décrire la dynamique d'un système de particules dans la région spinodale. Ensuite, avec des approches de champ moyen, nous étudions quels modes devraient conduire une source nucléaire à se fragmenter, nous discutons l'influence des non-linéarités, de la température, des effets de taille finie, de la portée des forces et des effets quantiques sur le développement des instabilités.